This invention relates to compositions of matter useful as additives for lubricants, to a method for their preparation, and to additive concentrates and lubricants containing them. In one embodiment, the invention includes oil-soluble boron-containing compositions prepared by reacting boric acid or boron trioxide with an epoxide having at least eight carbon atoms.
The increasing sophistication of internal combustion engines necessitates the development of new types of lubricants for use in them. The new engines in many instances operate under far more severe conditions than was formerly the case, and the lubricants must be tailored so as to permit them to be used over prolonged periods of time under those severe conditions.
As an example of the diverse types of requirements for lubricants, consideration should be given to diesel engines in heavy machinery. The lubricant performance requirements in such engines are much different from those in gasoline engines for automobiles. Nevertheless, it is frequently advantageous to formulate a single multi-purpose lubricant for use in both types of engines.
The severity of the conditions in diesel heavy machinery engines requires the presence in the lubricant of relatively high levels of ashless dispersants and/or ashproducing detergents. For example, many such lubricants contain basic alkaline earth metal phenates in amounts of 2.5% by weight or higher, and/or free hydroxy group-containing alkenylsuccinic acid ester dispersants in amounts of 1.5% or higher. The use of such lubricants in ordinary gasoline engines frequently causes a high degree of wear on engine parts. Conventional anti-wear agents such as zinc dialkylphosphorodithioates are, in many instances, not entirely effective in eliminating this problem.
Resinous products obtained by reacting 0.1 to 4 parts by weight of boron trioxide with one part of a monoepoxide compound having a boiling point above 50.degree. C. are described in UK Patent No. 931,000. The preparation of oil soluble surface active organic boron compound by reacting one mole of boric acid with from one to two moles of alphaolefin oxide having 10 to 32 carbon atoms in the presence of water is described in Japanese Appln. No. 48/14627 and abstracted in Chemical Abstracts, 95, 99685y (1981).